IBM 6151 Maintenance And Service Manual page 173

Step 3
1. Set the power switch on the system unit to Off.
2. Remove the top cover. If needed see Section 4.
3. Disconnect the power connectors to the diskette drive and
fixed-disk drive.
4. Set the power switch on the system unit to On.
DO YOU STILL HAVE A NOISE PROBLEM?
YES Do the following:
1. Exchange the cooling fan.
2. Connect the power connectors to the drives.
3. Run the System Checkout.
4. This completes the repair.
NO
Continue on the next page.
(6/88) Problem Isolation Charts
3·0050-3